<http://schema.org/description>
"Colour-light signalling, a modern innovation in the early 1960s, on an electrified railway line. Electrification of busy routes demanded a system of train control that was rapid and reliable; a demand met by this signalling system. Photograph by Heinz Zinram"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.mediastorehouse.com/railway-signal-at-night/print/4420803.html>